Preparation of YBCO Superconducting Thick Films on MgO Substrates by Modified Melt Growth Process

Superconducting thick films (200–300 μm) of YBCO have been fabricated successfully on MgO substrates by a new approach. The precursor powders (YBa2Cu3O7−δ (Y123) + 0.1 mol Y2BaCuO5(Y211)) are placed between two MgO (10 mm×10 mm) slices to form sandwich structure. The YBCO thick films have been obtained from the precursors by modified melt growth process. Resistance measurements of YBCO thick films show Tcon of 87.3 K and Δ T of 4.5 K. Estimates using hysteresis loops and the Bean model give a value of 2.78×103 A/cm2 (77 K, 0T) for the critical current density. The observations of scanning electron microscopy (SEM) and X-ray diffraction (XRD) patterns show the supercoducting Y123 phase matrix containing discrete Y211 inclusions.